Phase diagrams for liquid-crystalline binary systems of sodium palmitate with sodium butyrate, isobutyrate, or methylbutyrate

Differential thermal analysis and polarizing microscopy have been used to study phase equilibria at temperatures from 20 to 400°C and to determine the temperature and concentration ranges of existence for ionic liquid crystals (LCs) in binary systems formed by sodium alkanoates with different aliphatic chain lengths, namely, systems formed by long-chain sodium palmitate and a short-chain sodium alkanoate (butyrate, isobutyrate, 2-methylbutyrate). Terminal smectic (type A) LC solutions have been found in all systems. The effect of the radical geometry of the short-chain alkanoate anion on the thermostability of the sodium palmitate-based binary LC solution is discussed.